Enzymes

AAA+ proteases are ATP-powered molecular motors that thread protein chains through a hole

ABO blood types are determined by an enzyme that attaches sugars to proteins

In plants, AHAS performs the first step in synthesis of three essential amino acids, making it an effective target for herbicides.

Acetylcholinesterase stops the signal between a nerve cell and a muscle cell

Aconitase performs a reaction in the citric acid cycle, and moonlights as a regulatory protein

Alcohol dehydrogenase detoxifies the ethanol we drink

Amylases digest starch to produce glucose

Aminoacyl-tRNA synthetases ensure that the proper amino acids are used to build proteins

Anabolic steroids like testosterone are among the most common performance enhancing drugs

Key biosynthetic enzymes are regulated by their ultimate products through allosteric motions.

Beta-galactosidase is a powerful tool for genetic engineering of bacteria

Beta-secretase trims proteins in the cell and plays an important role in Alzheimer's disease

PKA delivers cellular signals by adding phosphates to proteins

Carbonic anhydrase solubilizes carbon dioxide gas so we can breathe it out

Light-sensing retinal molecules are built from colorful carotenoids in our diet

Caspases disassemble proteins during the process of programmed cell death

Catalase protects us from dangerous reactive oxidizing molecules

Citrate synthase opens and closes around its substrates as part of the citric acid cycle

Eight enzymes form a cyclic pathway for energy production and biosynthesis

Aspirin attacks an important enzyme in pain signaling and blood clotting

Cytochrome p450 detoxifies and solubilizes drugs and poisons by modifying them with oxygen

Bacteria destroy toxic environmental pollutants that include chlorine or bromine atoms.

DHFR is a target for cancer chemotherapy and bacterial infection

DNA ligase reconnects broken DNA strands, and is used to engineer recombinant DNA

The weedkiller Roundup attacks a key enzyme involved in the construction of aromatic compounds.

Exosomes destroy messenger RNA molecules after they have finished their jobs

Fatty acids are constructed in many sequential steps by a large protein complex

Bacteria adhere to our teeth by building sticky sugar chains

Glucose oxidase measures blood glucose level in biosensors

Glutamine synthetase monitors the levels of nitrogen-rich amino acids and decides when to make more

Glycogen phosphorylase releases sugar from its cellular storehouse

The ten enzymes of glycolysis break down sugar in our diet

HIV builds a DNA copy of its RNA genome, providing a unique target for drug therapy

Hydrogenases use unusual metal ions to split hydrogen gas

Cells salvage and recycle their obsolete DNA and RNA

Atomic structures have revealed the catalytic steps of a citric acid cycle enzyme

Our cells temporarily build lactate when supplies of oxygen are low

Legumain cleaves proteins, and can also put them back together.

Organisms from fireflies to bacteria use luciferase to emit light

Lysozyme attacks the cell walls of bacteria

Methanogens use sophisticated molecular tools to build methane

Antibiotics can save lives, but antibiotic-resistant strains of bacteria pose a dangerous threat

Nitrogenase uses an exotic cluster of metals to fix atmospheric nitrogen into bioavailable ammonia

Some protein functions are regulated when sugars are attached

Oxidosqualine cyclase forms the unusual fused rings of cholesterol molecules

Pepsin digests proteins in strong stomach acid

An unusual cofactor is used in the synthesis of aromatic amino acids

Phytase is used in agriculture to mobilize indigestible phosphate compounds in livestock feed.

Poly(A) polymerase adds a long tail of adenine nucleotides at the end of messenger RNA

A huge molecular complex links three sequential reactions for energy production

Bacterial enzymes that cut DNA are useful tools for genetic engineering

Some proteases cut proteins embedded in cell membranes

Ribonuclease cuts and controls RNA

Ribonucleotide reductase creates the building blocks of DNA

Ribosomes are complex molecular machines that build proteins

RNA polymerase transcribes genetic information from DNA into RNA

Rubisco fixes atmospheric carbon dioxide into bioavailable sugar molecules

Selenium is used in place of sulfur to build proteins for special tasks

Special sequences of RNA are able to splice themselves

Growth signaling proteins play an important role in the development of cancer

Sulfotransferases transfer sulfuryl groups in enzymatic reactions

Superoxide dismutase protects us from dangerously reactive forms of oxygen

Tetrahydrobiopterin plays an essential role in the production of aromatic amino acids, neurotransmitters and nitric oxide.

Thrombin activates the molecule that forms blood clots

Ultraviolet light damages our DNA, but our cells have ways to correct the damage

Tissue transglutaminase staples proteins together by forming a chemical crosslink.

Topoisomerases untangle and reduce the tension of DNA strands in the cell

Transposases shift genes around in the genome

An activated serine amino acid in trypsin cleaves protein chains

Xanthine oxidoreductase helps break down obsolete purine nucleotides